gtk-im-extra is a collection of third party GTK+ input method modules.

rationale

Many GTK+ input methods are fairly simple; they don’t do much more than
compose characters from sequences
of keystrokes. Such input methods, of which there are
several
examples in GTK+ itself, are usually contained in a single source
file a few hundred lines in length.
It’s a lot of overhead for the programmer and the
user to have to deal with a separate package for every such third party
module. gtk-im-extra is a clearinghouse for anybody who doesn’t want to
go to the trouble of packaging his or her own module. (Note that you
are welcome to ask me to include your input module even if it isn’t
particularly simple.)

download

There have been no releases of gtk-im-extra yet. You can check out the
source from cvs: